1. Field of the Invention
The present invention relates to an electrical junction box which houses fuses and relay parts in a case thereof.
2. Description of the Related Art
As a conventional electrical junction box of this kind, one is disclosed in DE Patent Application Laid-Open No. 3209915. As shown in FIG. 1, in this electrical junction box 50, a relay part 52 is housed in a case 51. In the case 51, a fuse mounting part 53 is provided above the relay part 51. A fuse 54 is freely attached/detached to/from the fuse mounting part 53 from above the case 51.
The electrical junction box 50 described above has an advantage that a state of the fuse 54 can be inspected, and the fuse 54 can be replaced, from above the case 51.
However, in the conventional electrical junction box 50, the fuse mounting part 53 is disposed in a state of being exposed to an upper surface of the case 51. It is unavoidable that a water droplet or the like resulting from dew condensation enters the case 51 through the fuse mounting part 53. When water enters the case 51, there is a problem that failure is caused by the water wetting the relay part 52 and the like.
Moreover, as an electrical junction box mounted on a vehicle, there is one in which a branch circuit for distributing and supplying power for a vehicle to each load of the vehicle is of conductive bus bars having high rigidity (Japanese Patent Application Laid-Open No. 5 (1993)-54787). As a configuration of the electrical junction box described above, the electrical junction box includes: a first bus bar in which one set of fuse terminals and the like are integrally formed; a second bus bar in which the other set of fuse terminals and the like are integrally formed; and a bus bar insulating block body which is fixed to the second bus bar. By attaching the first bus bar to the bus bar insulating block body, the first and second bus bars are positioned in correct relative positions. The first and second bus bars which are assembled as described above are housed in the case.
Incidentally, with regard to a positioning structure in which a first bus bar and a bus bar insulating block body are assembled in correct relative positions, the following structure is generally adopted. Specifically, the first bus bar is fitted to a surface of the bus bar insulating block body where the first bus bar is attached. Thereafter, a concave groove which is one step lower than a surrounding surface is formed. Subsequently, the first bus bar and the bus bar insulating block body are assembled in correct relative positions by fitting the first bus bar into the concave groove.
However, in the positioning structure described above, it is required to align the first bus bar with the concave groove of the bus bar insulating block body as a whole. Moreover, the concave groove of the bus bar insulating block body is formed to have a depth which is almost equal to a thickness of the first bus bar. Thus, sometimes, it is impossible to easily determine whether or not the first bus bar is in a state of being completely fitted into the concave groove of the bus bar insulating block body. Consequently, there may be a problem of poor assembly workability. When the first bus bar and the bus bar insulating block body are not assembled in appropriate positions, the first and second bus bars are not assembled in correct relative positions. Accordingly, for example, a pair of fuse terminals formed between the bus bars is in a state of being out of position. Therefore, there arises a problem of causing mounting failure of fuses or the like.
Moreover, in an electrical junction box described above, in order to achieve miniaturization, a plurality of relay parts are put together and arranged in the case. Thus, a large amount of heat is generated. Particularly, in an electrical junction box which distributes and supplies a large current, a means for radiating the heat are essential. Here, in order to improve a heat radiation property, it is considered to elongate the second bus bar in a straight manner and increase a heat radiation area. However, such an electrical junction box comes large in size.